US20220350263A1 - Wafer stage and method thereof - Google Patents
Wafer stage and method thereof Download PDFInfo
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- US20220350263A1 US20220350263A1 US17/468,432 US202117468432A US2022350263A1 US 20220350263 A1 US20220350263 A1 US 20220350263A1 US 202117468432 A US202117468432 A US 202117468432A US 2022350263 A1 US2022350263 A1 US 2022350263A1
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- wafer stage
- laser beam
- beam splitter
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- sidewall
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Images
Classifications
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- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
- H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
- H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
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- G03F7/2004—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light
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- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
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Definitions
- IC semiconductor integrated circuit
- functional density i.e., the number of interconnected devices per chip area
- geometry size i.e., the smallest component (or line) that can be created using a fabrication process
- This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs.
- Such scaling down has also increased the complexity of IC processing and manufacturing.
- similar developments in IC processing and manufacturing are needed. For example, the need to perform higher resolution lithography processes grows.
- One lithography technique is extreme ultraviolet lithography (EUVL).
- EUVL extreme ultraviolet lithography
- Other techniques include X-Ray lithography, ion beam projection lithography, electron beam projection lithography, and multiple electron beam maskless lithography.
- FIG. 1 is a schematic view of a lithography system in accordance with some embodiments of the present disclosure.
- FIG. 2 is a schematic view of a lithography system in accordance with some embodiments of the present disclosure.
- FIGS. 3A and 3B are a schematic view of a wafer table of a lithography chamber in accordance with some embodiments of the present disclosure.
- FIG. 4A is a schematic view of a wafer stage of a lithography chamber in accordance with some embodiments of the present disclosure.
- FIG. 4B to FIG. 4D are partial views of the wafer stage of FIG. 4A in accordance with some embodiments of the present disclosure.
- FIG. 5 illustrates a method of operating a lithography system in accordance with some embodiments of the present disclosure.
- FIGS. 6A to 6C are schematic views of a lithography chamber in various stages of operations in accordance with some embodiments of the present disclosure.
- first and second features are formed in direct contact
- additional features may be formed between the first and second features, such that the first and second features may not be in direct contact
- present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
- spatially relative terms such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures.
- the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.
- the apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
- fin-type field effect transistors FinFETs
- the fins may be patterned to produce a relatively close spacing between features, for which the above disclosure is well suited.
- spacers used in forming fins of FinFETs can be processed according to the above disclosure.
- FIG. 1 is a schematic view of lithography system in accordance with some embodiments of the present disclosure. Shown there is a EUV lithography system 10 . Although the EUV lithography system 10 is illustrated as having a certain configuration of components, it will be appreciated that the disclosed lithography system 10 may include additional components (e.g., additional mirrors) or having less components (e.g., less mirrors).
- additional components e.g., additional mirrors
- less components e.g., less mirrors
- the EUV lithography system 10 includes a EUV source vessel 110 .
- a fuel droplet generator 120 is connected to the EUV source vessel 110 and is configured to generate a plurality of fuel droplets 112 .
- the fuel droplets 112 generated by the fuel droplet generator 120 are provided into the EUV source vessel 110 .
- the fuel droplets 112 may include tin (Sn).
- the fuel droplets 112 may include a different metal material.
- the EUV source vessel 110 can also be referred to as a radiation source, in which radiation source employs a laser produced plasma (LPP) mechanism to generate plasma and further generate EUV light from the plasma.
- LPP laser produced plasma
- the EUV lithography system 10 may also include a droplet position detection system which may include a droplet imager 140 disposed in the EUV source vessel 110 that captures an image of one or more fuel droplets 112 .
- the droplet imager 140 may provide this captured image to a droplet position detection feedback system (not shown), which can, e.g., generate a droplet position and trajectory in response to an analysis result of the captured image.
- the position detection feedback system can thus generate a droplet error in response to the generated droplet position and trajectory, e.g., based on a droplet-by-droplet basis, or on average.
- the droplet imager 140 may include a fine droplet steering camera (FDSC), a droplet formation camera (DFC), and/or suitable devices.
- FDSC fine droplet steering camera
- DFC droplet formation camera
- the EUV lithography system 10 further includes a primary laser having a laser source 102 configured to produce a laser beam 104 .
- the laser source 102 may include a multi-stage laser having a plurality of stages configured to amplify laser light produced by a prior stage.
- the laser beam 104 passes through a beam transport system 106 configured to provide the laser beam to a focusing system 108 .
- the focusing system 108 includes one or more lenses 108 a , 108 b and/or mirrors arranged within a beam line and configured to focus the laser beam 104 .
- the laser beam 104 is output from the focusing system 108 to the EUV source vessel 110 .
- the laser beam 104 transmits through a collector mirror 118 located within the EUV source vessel 110 . Then, the primary laser beam 104 generated by the laser source 102 intersects the fuel droplets 112 .
- the primary laser beam 104 may be a carbon dioxide (CO 2 ) laser. In other embodiments, the primary laser beam 104 may include alternative types of lasers.
- the primary laser beam 104 strikes the fuel droplets 112 , the primary laser beam 104 heats the fuel droplets 112 to a predetermined temperature. At the predetermined temperature, the fuel droplets 112 shed their electrons and become a plasma 114 including a plurality of ions.
- the ions emit EUV radiation 116 (e.g., having a wavelength of approximately 13.3 nm to about 13.7 nm).
- the collector mirror 118 has a concave curvature.
- the collector mirror 118 may include a multi-layer coating having alternating layers of different materials.
- the collector mirror 218 may include alternating layers of molybdenum and silicon configured to operate as a Bragg reflector.
- the concave curvature of the collector mirror 218 focuses the EUV radiation 116 generated by the plasma 114 toward an intermediate focus (IF) unit 130 within an exit aperture of the EUV source vessel 110 .
- the intermediate focus unit 130 is located between the EUV source vessel 110 and a scanner 200 including optical elements configured to direct the EUV radiation 116 to a workpiece (e.g., a semiconductor substrate).
- the intermediate focus unit 130 may include a cone shaped aperture configured to provide for separation of pressures between the EUV source vessel 110 and the scanner 200 .
- the intermediate focus unit 130 may extend into the scanner 200 .
- the EUV lithography system 10 may also include an EUV energy monitor 150 disposed in the EUV source vessel 110 .
- the EUV energy monitor 150 is designed to monitor the EUV intensity or energy generated from the EUV source vessel 110 .
- the EUV energy monitor 150 includes an EUV sensing element, such as a diode, designed to be sensitive to the EUV light and configured to effectively detect the EUV light.
- the EUV energy monitor 150 includes a plurality of diodes configured in an array to effectively detect the EUV light for monitoring purpose.
- a dose error is calculated based on the sensed EUV intensity (or energy). For example, when the sensed EUV intensity (or energy) is below a predetermined threshold value, such situation can be referred to as a dose error.
- the dose error is related to the plasma instability, through monitoring the EUV intensity by the EUV energy monitor 150 , the dose error can be extracted from the monitored EUV intensity. Therefore, when a dose error is occurred, it indicates that the plasma 114 is unstable.
- the EUV lithography system further includes a droplet collection element 125 disposed in the EUV source vessel 110 and located opposite to the droplet generator 120 .
- the droplet collection element 125 is configured to collect fuel droplets 112 that are not vaporized during formation of the EUV radiation 116 and/or fragments of fuel droplets 112 generated during formation of the EUV radiation 116 .
- the EUV radiation 116 output from the EUV source vessel 110 is provided to a condenser 210 by way of the intermediate focus unit 130 .
- the condenser 210 includes first and second surfaces 212 a and 212 b configured to focus the EUV radiation 116 , and a reflector 214 configured to reflect the EUV radiation 116 towards an EUV photomask 220 .
- the EUV photomask 220 is configured to reflect the EUV radiation 116 to form a pattern on a surface of a semiconductor wafer 250 .
- the EUV photomask 220 may include a plurality of absorptive features 222 a , 222 b , and 222 c arranged on a front surface of the EUV photomask 220 .
- the plurality of absorptive features 222 a , 222 b , and 222 c are configured to absorb the EUV radiation 116 , such that the reflected rays of EUV radiation 116 conveys a patterned defined by the EUV photomask 220 .
- the EUV radiation 116 is filtered through reduction optics including a series of first to fourth mirrors 230 a , 230 b , 230 c , and 230 d , which serve as lenses to reduce a size of the pattern carried by the EUV radiation 116 .
- the fourth mirror 230 d is the last mirror that directly reflects the EUV radiation 116 from previous mirrors onto a on a layer of photoresist coated on a surface of the semiconductor wafer 250 .
- the EUV radiation 116 irradiates particular regions of the layer of photoresist based on the pattern carried by the EUV radiation 116 , and thus the layer of irradiated photoresist layer can be patterned after developing it. Therefore, subsequent processing can be performed on selected regions of the semiconductor wafer 250 .
- FIG. 2 is a schematic view of a lithography system 20 according to the present disclosure.
- the lithography system 20 may be applied to pattern semiconductor wafers, as discussed above with respect to the semiconductor wafer 250 of FIG. 1 .
- the wafers 250 are indicated by dashed circles.
- the wafers are moved from a wafer handler 260 , through load locks 264 , 265 and a wafer exchange chamber 266 , to a lithography chamber 271 . It is understood that the lithography process discussed in FIG. 1 is performed when the wafer 250 is positioned in the lithography chamber 271 .
- the wafers 250 in the wafer handler 260 may have been undergone several processes, such as resist-apply, pre-bake, and other processes . . . etc.
- wafers are returned to the wafer handler 260 for further processing steps, such as development, post bake, and the like.
- the wafer handler 260 is separated from the load locks 264 , 264 by gate valve assemblies 262 , 263 .
- the load locks 264 , 265 are separated from the wafer exchange chamber 266 by gate valve assemblies 267 , 268 .
- the load locks 264 , 265 can also be referred to as chambers that are separated from the wafer handler 260 and the wafer exchange chamber 266 by respective gate valve assemblies 267 , 268 .
- the load locks 264 , 265 may further be connected to vacuum and venting elements (not shown) that allow the load locks 264 , 265 to be transitioned from atmospheric pressure to vacuum (pumped-down) and back to atmospheric pressure again (vented).
- the wafer exchange chamber 266 can be held at a high vacuum while wafer handler 260 is held at atmospheric pressure.
- the load locks 264 , 265 thus serve to move wafers in and out from the wafer exchange chamber 266 while transitioning from atmospheric pressure to high vacuum.
- the wafer exchange chamber 266 may include a robot arm 269 .
- the robot arm 269 is used to transfer wafers from the load locks 264 , 265 to the lithography chamber 271 .
- the robot arm 269 may include a single end-effector, or dual, non-robotic, transport mechanisms could also be used without departing from the scope of the present disclosure.
- the wafer exchange chamber 266 is connected to lithography chamber 271 through a gate valve assembly 270 .
- the lithography chamber 271 includes wafer stages 272 , 273 .
- the wafer stages 272 , 273 are capable of movement in the directions indicated for fine alignment and exposure processes.
- the lithography chamber 271 thus further includes projection optics or other elements necessary to perform the lithography patterning. While lithography chamber 271 is illustrated to have two wafer stages 272 , 273 , less or more wafer stages may also be employed.
- FIGS. 3A and 3B illustrate different views of a wafer table of a lithography chamber in accordance with some embodiments of the present disclosure. It is noted that the lithography chamber 400 discussed in FIGS. 3A and 3B is similar to the lithography chamber 271 discussed in FIG. 2 .
- the lithography chamber 400 includes a table body 410 (e.g., stage frame).
- the table body 410 includes a top surface 4101 , a sidewall 4102 , a sidewall 4103 , a sidewall 4104 , and a sidewall 4105 .
- the sidewall 4102 is connected to the sidewalls 4103 and 4105 , and is opposite to the sidewall 4104 .
- the sidewall 4103 is connected to the sidewalls 4102 and 4104 , and is opposite to the sidewall 4105 .
- the sidewall 4104 is connected to the sidewalls 4103 and 4105 , and is opposite to the sidewall 4102 .
- the sidewall 4105 is connected to the sidewalls 4102 and 4104 , and is opposite to the sidewall 4103 .
- At least one wafer stage 415 is movably disposed on the table body 410 , in which the table body 410 may include a flat, level top surface 4101 over which the wafer stage 415 can move.
- a wafer W may be disposed on a top surface 4151 of the wafer stage 415 .
- the wafer stage 415 here can be similar to the wafer stages 272 , 273 discussed in FIG. 2 .
- the wafer stage 415 may be coupled to the table body 410 in a non-contact manner.
- the table body 410 may include a magnet array (stator) of a planar motor while the coil units are built inside the wafer stage 415 , so that the wafer stage 415 can be suspended above the table body by using magnetic levitation.
- the wafer stage 415 can be suspended above the table body 410 with no support other than magnetic field generated from the table body 410 , and the magnetic force can be used to counteract the effects of gravitational acceleration. In this way, the wafer stage 415 can be horizontally moved above the table body 410 without contacting the table body 410 .
- the wafer stage 415 is supported by magnetic levitation above the table body 410 in a non-contact manner by a predetermined clearance, such as around several ⁇ m, by adjusting the balance of the upward force (repulsion) such as the electromagnetic force and the downward force (gravitation) including the self-weight, and is also finely driven at least in directions of two degrees of freedom, which are the X-axis direction and the Y-axis direction by using a driving mechanism.
- the electromagnetic force can be controlled to raise or lower the wafer stage 415 , so that the wafer stage 415 have an additional degree of freedom on the Z-axis direction as well.
- the wafer stage 415 includes a top surface 4151 , a sidewall 4152 , a sidewall 4153 , a sidewall 4154 , and a sidewall 4155 .
- the sidewall 4152 is connected to the sidewalls 4153 and 4155 , and is opposite to the sidewall 4154 .
- the sidewall 4153 is connected to the sidewalls 4152 and 4154 , and is opposite to the sidewall 4155 .
- the sidewall 4154 is connected to the sidewalls 4153 and 4155 , and is opposite to the sidewall 4152 .
- the sidewall 4155 is connected to the sidewalls 4152 and 4154 , and is opposite to the sidewall 4153 .
- the sidewalls 4152 , 4153 , and 4154 of the wafer stage 415 are substantially vertical to the top surface 4101 of the table body 410 .
- the sidewall 4155 is an inclined surface, which is tilted about 45° relative to the top surface 4101 of the table body 410 . Stated another way, the sidewall 4155 forms an angle about 45° with the top surface 4101 of the table body 410 .
- the wafer stage 415 is horizontally movable between a first station ST 1 and a second station ST 2 of the table body 410 .
- the horizontal motion can be controlled by a motor coupled to the wafer stage 415 , and a range of horizontal motion is sufficient to transfer the wafer stage 415 from the first station ST 1 to the second station ST 2 , and also sufficient to transfer the wafer stage 415 from the second station ST 2 to the first station ST 1 .
- the lithography chamber 400 includes an alignment sensor 530 above the wafer stage 415 .
- the alignment sensor 530 can measure alignment marks provided on the wafer W disposed on the wafer stage 415 , such that the exact position of the wafer W can be measured, and therefore the wafer W can be properly aligned with a patterning device.
- the wafer stage 415 is moved to the second station ST 2 (e.g., see FIG. 6C )
- an exposure process can be performed to the wafer W disposed on the wafer stage 415 through a projection system 532 above the wafer stage 415 .
- the projection system 532 may include, for example, the condenser 210 of FIG. 1 , the photomask 220 of FIG.
- the wafer stage 415 is at the second station ST 2 (e.g., see FIG. 6C )
- an exposure process can be performed to a layer of photoresist coated on the wafer W, so as to pattern the layer of photoresist.
- the first station ST 1 is serve to perform the alignment process and the second station ST 2 is serve to perform the exposure process
- the first station ST 1 can be referred to as an alignment station
- the second station ST 2 can be referred to as an exposure station.
- the lithography chamber 400 also includes a first sliding member 420 and a second sliding member 430 , which are used to move the wafer stage 415 over the top surface 4101 of the table body 410 .
- the second sliding member 430 has a first portion 430 A extending along the top surface 4101 of the table body 410 , and a second portion 430 B on the sidewall 4102 of the table body 410 .
- the second portion 430 B of the second sliding member 430 is coupled to a slot 412 on the sidewall 4102 of the table body 410 , such that the second sliding member 430 can be movable along the slot 412 at the sidewall 4102 of the table body 410 in a first direction (e.g., the X direction).
- the second sliding member 430 further includes a track 432 coupled to the first portion 430 A.
- the track 432 extends along the top surface 4101 of the table body 410 and extends in a second direction (e.g., the Y direction).
- the first sliding member 420 is movably mounted on the track 432 of the second sliding member 430 , such that the first sliding member 420 can be movable along the track 432 of the second sliding member 430 in a second direction (e.g., the Y direction).
- the first sliding member 420 is further coupled to the wafer stage 415 .
- the wafer stage 415 is also coupled to the second sliding member 430 through the first sliding member 420 .
- the wafer stage 415 is movable over the top surface 4101 of the table body 410 along a plane (e.g., X-Y plane) constructed by the first direction (e.g., the X direction) and the second direction (e.g., the Y direction).
- the wafer stage 415 can move along the first direction (e.g., the X direction) when the second sliding member 430 is actuated to move along the slot 412 on the sidewall 4102 of the table body 410 , and can move along the second direction (e.g., the Y direction) when the first sliding member 420 is actuated to move along the track 432 of the second sliding member 430 .
- first direction e.g., the X direction
- second direction e.g., the Y direction
- the lithography chamber 400 further includes a plurality of cables 440 A, 440 B, 440 C, and 440 D with utilities.
- the cables 440 A, 440 B, 440 C, and 440 D are connected to the sidewall 4152 of the wafer stage 415 .
- the cable 440 A is connected to a gas source 502
- the cable 440 B is connected to a gas source 504
- the cable 440 C is connected to a liquid source
- the cable 440 D is connected to a power source 508 .
- the gas source 502 may be a hydrogen (H 2 ) source, which provides hydrogen (H 2 ) gas into the wafer stage 415 .
- the gas source 504 may be an extreme clean dry air (XCDA) source, which provides extreme clean dry air into the wafer stage 415 .
- the liquid source 506 may be a water (H 2 O) source, which provides water into the wafer stage 415 .
- the power source 508 may be a power supplier, which provides electrical power to the wafer stage 415 .
- Brackets 460 are configured to fix the cables 440 A to 440 D together, such that the cables 440 A to 440 D may be arranged neatly and in a desired order. Furthermore, the cable 440 A to 440 D may be movable along with each other.
- Gate valve assembly 450 is disposed close to the sidewall 4103 of the table body 410 .
- the gate valve assembly 450 may be similar to the gate valve assembly 270 described in FIG. 2 .
- a robot arm e.g., the robot arm 269 of FIG. 2
- the gate valve assembly 450 is not illustrated in FIG. 3A for clarity.
- the lithography chamber 400 also includes a plurality of stage positioning modules 510 , 512 , 514 , and 516 .
- the stage positioning module 510 is disposed at the side of the sidewall 4103 of the table body 410 .
- the stage positioning modules 512 and 514 are disposed at the side of the sidewall 4104 of the table body 410 , and are spaced apart from each other along the first direction (e.g., X direction).
- the stage positioning module 516 is disposed at the side of the sidewall 4105 of the table body 410 .
- the stage positioning module 510 may include a laser emitter aimed at the sidewall 4153 of the wafer stage 415 , and a sensor adjacent to the laser emitter.
- the laser emitter of the stage positioning module 510 can emit a laser beam to the sidewall 4153 of the wafer stage 415 .
- the sidewall 4153 can reflect the laser beam back to the stage positioning module 510 , such that the sensor adjacent to the laser emitter can measure the position of the wafer stage 415 along the first direction (e.g., X direction).
- the stage positioning module 512 may include a laser emitter and a sensor adjacent to the laser emitter.
- the laser emitter can be aimed at the sidewall 4154 of the wafer stage 415 .
- the laser emitter of the stage positioning module 512 can emit a laser beam to the sidewall 4154 of the wafer stage 415 .
- the sidewall 4154 can reflect the laser beam back to the sensor adjacent to the laser emitter, such that the stage positioning module 512 can measure the position of the wafer stage 415 along the second direction (e.g., Y direction) when the wafer stage 415 is at the first station ST 1 .
- the stage positioning module 514 may include a laser emitter and a sensor adjacent to the laser emitter.
- the laser emitter can be aimed at the sidewall 4154 of the wafer stage 415 .
- the laser emitter of the stage positioning module 514 can emit a laser beam to the sidewall 4154 of the wafer stage 415 .
- the sidewall 4154 can reflect the laser beam back to the sensor adjacent to the laser emitter, such that the stage positioning module 514 can measure the position of the wafer stage 415 along the second direction (e.g., Y direction) when the wafer stage 415 is at the second station ST 2 .
- the lithography chamber 400 also includes a plurality of sensors 520 and 522 disposed over the table body 410 .
- the sensor 520 is optically coupled to the stage positioning module 516 .
- the stage positioning module 516 may include a laser emitter aimed at the sidewall 4155 of the wafer stage 415 .
- the laser emitter of the stage positioning module 516 can emit a laser beam to the sidewall 4155 of the wafer stage 415 .
- the sidewall 4155 of the wafer stage 415 can reflect the laser beam upwardly to the sensor 520 , such that the sensor 520 and the stage positioning module 516 can collectively measure the position of the wafer stage 415 along a third direction (e.g., Z direction) when the wafer stage 415 is at the first station ST 1 .
- a third direction e.g., Z direction
- the sensor 522 is optically coupled to the stage positioning module 516 .
- the laser emitter of the stage positioning module 514 can emit a laser beam to the sidewall 4155 of the wafer stage 415 , and the sidewall 4155 of the wafer stage 415 can reflect the laser beam upwardly to the sensor 522 , such that the sensor 522 and the stage positioning module 516 can collectively measure the position of the wafer stage 415 along the third direction (e.g., Z direction) when the wafer stage 415 is at the second station ST 2 .
- the third direction e.g., Z direction
- FIG. 4A is a schematic view of a wafer stage of a lithography chamber in accordance with some embodiments of the present disclosure.
- FIG. 4B to FIG. 4D are partial views of the wafer stage of FIG. 4A in accordance with some embodiments of the present disclosure.
- FIG. 4A illustrates a detailed configuration of the wafer stage 415 discussed in FIGS. 3A and 3B , in which the perspective view of the wafer stage 415 in FIG. 4A is the same as the perspective view of the wafer stage 415 in FIG. 3B .
- the sidewall 4153 of the wafer stage 415 includes a beam splitter 603
- the sidewall 4154 of the wafer stage 415 includes a beam splitter 604
- the sidewall 4155 of the wafer stage 415 includes a beam splitter 605
- the sidewall 4152 of the wafer stage 415 does not include a beam splitter.
- the sidewall 4152 of the wafer stage 415 is connected to the cables 440 A to 440 D, and thus the sidewall 4152 of the wafer stage 415 may be made of a material different from a material of the beam splitter.
- the outer surfaces of the beam splitters 603 and 604 are substantially vertical to the top surface 4101 of the table body 410 (see FIGS. 3A and 3B ). In some embodiments, the surface of the outer surface of the beam splitter 605 is tilted about 45° relative to the top surface 4101 of the table body 410 (see FIGS. 3A and 3B ).
- the wafer stage 415 includes sensors 613 , 614 , and 615 disposed inside the body of the wafer stage 415 , in which a sensing surface of the sensor 613 faces the beam splitter 603 at the sidewall 4153 of the wafer stage 415 , a sensing surface of the sensor 614 faces the beam splitter 604 at the sidewall 4154 of the wafer stage 415 , and the sensing surface of the sensor 615 faces the beam splitter 605 at the sidewall 4155 of the wafer stage 415 .
- the sensing surfaces of the sensors 613 , 614 , and 615 are vertical to the top surface 4101 of the table body 410 (see FIGS. 3A and 3B ).
- the sensing surfaces of the sensors 613 and 614 are substantially parallel to the outer surfaces of the beam splitters 603 and 604 , respectively, and are parallel to the sidewalls 4153 and 4154 of the wafer stage 415 , respectively.
- the sensing surface of the sensor 615 is tilted about 45° relative to the outer surface of the beam splitter 605 and the sidewall 4155 of the wafer stage 415 .
- the wafer stage 415 includes a processor 620 electrically coupled to the sensors 613 , 614 , and 615 , and a controller 630 electrically coupled to the processor 620 .
- the processor 620 can process the signal received from the sensors 613 , 614 , and 615 .
- the processor 620 and the controller 630 may include, for example, a central processing unit (CPU), a microprocessor, a programmable logic control unit, a computer or other device or system that is adapted to perform the functions described herein.
- FIG. 4B Shown there is a relative position among the stage positioning module 512 (or 514 ), the beam splitter 604 at the sidewall 4154 of the wafer stage 415 , and the sensor 614 .
- the stage positioning module 512 (or 514 ) may be used to measure the position of the wafer stage 415 .
- the stage positioning module 512 may emit a laser beam LB 1 toward the wafer stage 415 , such that the laser beam LB 1 is incident on an incident surface of the beam splitter 604 .
- the laser beam LB 1 is split, by the beam splitter 604 , into a laser beam LB 11 and a laser beam LB 12 , in which the laser beam LB 11 is the laser beam reflected by the beam splitter 604 , while the laser beam LB 12 is the laser beam transmitting through the beam splitter 604 .
- the laser beam LB 1 can be referred to as an incident laser beam
- the laser beam LB 11 can be referred to as a reflected laser beam
- the laser beam LB 12 can be referred to as a transmitted laser beam, respectively.
- the stage positioning module 512 can measure the position of the wafer stage 415 along the second direction (e.g., Y direction). For example, the stage positioning module 512 (or 514 ) can emit the laser beam LB 1 toward the beam splitter 604 on the wafer stage 415 , receive the reflected laser beam LB 11 from the beam splitter 604 , and therefore calculate the distance between the stage positioning module 512 (or 514 ) and the beam splitter 604 , which determines the position of the wafer stage 415 .
- the second direction e.g., Y direction
- the stage positioning module 512 (or 514 ) is able to send a control signal to control the wafer stage 415 .
- the stage positioning module 512 (or 514 ) can emit the laser beam LB 1 toward the beam splitter 604 on the wafer stage 415 .
- the laser beam LB 1 can be a modulated laser beam, which carries a control signal capable of triggering electrical and/or mechanical operations such as wafer stage movement/gas ejection/liquid ejection.
- a laser beam that does not carry any control signal is called an unmodulated laser beam, such as the laser beam used to measure position of the wafer stage 415 as discussed previously.
- the senor 614 in the wafer stage 415 can receive the transmitted laser beam LB 12 , and the processor 620 can decode the transmitted laser beam LB 12 to obtain the control signal carried by the transmitted laser beam LB 12 .
- the sensor 614 is optically coupled to the stage positioning module 512 (or 514 ) through the beam splitter 604 .
- the processor 620 further transmits the control signal to the controller 630 , and the controller 630 can control the wafer stage 415 in several manners.
- the controller 630 may control the wafer stage 415 , according to the control signal carried by the laser beam LB 1 , the position of the wafer stage 415 , the delivery of gas from the gas sources 502 , 504 (see FIG. 3A ), and the delivery of liquid from the liquid source 506 (see FIG. 3A ).
- the controller 630 can actuate the first sliding member 420 and the second sliding member 430 (see FIGS. 3A and 3B ), so as to move the wafer stage 415 to a desired position over the table body 410 , such as moving the wafer stage 415 to the first station ST 1 or to the second station ST 2 (see FIGS. 3A and 3B ).
- the position of the wafer stage 415 can be detected simultaneously by detecting the reflected laser beam LB 11 .
- the controller 630 can control a gas delivery to the wafer stage 415 .
- the gas source 502 may be a hydrogen (H 2 ) source
- the gas source 504 may be an extreme clean dry air (XCDA) source.
- the controller 630 may carry out a cleaning process by turning on a valve of the cable 440 A connected to the gas source 502 to introduce the gas from the gas source 502 (e.g., H 2 ) into the wafer stage 415 , and then ejecting the gas out of the wafer stage 415 to clean the wafer stage 415 , such as blowing particle away from top surface 4151 of the wafer stage 415 .
- the controller 630 may further carry out a purging process by turning on a valve of the cable 440 B connected to the gas source 504 to introduce the gas from the gas source 504 (e.g., XCDA) into the wafer stage 415 , and then ejecting the gas out of the wafer stage 415 to purge the gas from the gas source 502 (e.g., H 2 ) away.
- a purging process by turning on a valve of the cable 440 B connected to the gas source 504 to introduce the gas from the gas source 504 (e.g., XCDA) into the wafer stage 415 , and then ejecting the gas out of the wafer stage 415 to purge the gas from the gas source 502 (e.g., H 2 ) away.
- the controller 630 can control a liquid delivery to the wafer stage 415 .
- the liquid source 506 may be a water source.
- the controller 630 may carry out a cooling process by turning on a valve of the cable 440 C connected to the liquid source 506 to introduce the liquid from the liquid source 506 (e.g., water) into the wafer stage 415 .
- the cooling process may be performed after performing an exposure process to a wafer.
- FIG. 4C Shown there is a relative position among the stage positioning module 510 , the beam splitter 603 at the sidewall 4153 of the wafer stage 415 , and the sensor 613 .
- the stage positioning module 510 may be used to measure the position of the wafer stage 415 .
- the stage positioning module 510 may emit a laser beam LB 2 toward the wafer stage 415 , such that the laser beam LB 2 is incident on an incident surface of the beam splitter 603 .
- the laser beam LB 2 is split, by the beam splitter 603 , into a laser beam LB 21 and a laser beam LB 22 , in which the laser beam LB 21 is the laser beam reflected by the beam splitter 603 , while the laser beam LB 22 is the laser beam transmitting through the beam splitter 603 .
- the laser beam LB 2 can be referred to as an incident laser beam
- the laser beam LB 21 can be referred to as a reflected laser beam
- the laser beam LB 22 can be referred to as a transmitted laser beam, respectively.
- the stage positioning module 510 can measure the position of the wafer stage 415 along the first direction (e.g., X direction). For example, the stage positioning module 510 can emit the laser beam LB 2 toward the beam splitter 603 on the wafer stage 415 , receive the reflected laser beam LB 21 from the beam splitter 603 , and therefore calculate the distance between the stage positioning module 510 and the beam splitter 603 , which determines the position of the wafer stage 415 .
- the first direction e.g., X direction
- the stage positioning module 510 is able to send a control signal to control the wafer stage 415 .
- the stage positioning module 510 can emit the laser beam LB 2 toward the beam splitter 603 on the wafer stage 415 , while the laser beam LB 2 can be a modulated laser, which carries a control signal.
- the sensor 613 in the wafer stage 415 can receive the transmitted laser beam LB 22
- the processor 620 can decode the transmitted laser beam LB 22 to obtain the control signal carried by the transmitted laser beam LB 22 .
- the sensor 613 is optically coupled to the stage positioning module 510 through the beam splitter 603 .
- the processor 620 further transmits the control signal to the controller 630 , and the controller 630 can control the wafer stage 415 in several manners.
- the controller 630 may control the wafer stage 415 , according to the control signal carried by the laser beam LB 2 , the position of the wafer stage 415 , the delivery of gas from the gas sources 502 , 504 (see FIG. 3A ), and the delivery of liquid from the liquid source 506 (see FIG. 3A ).
- the control signal may be a position control signal, a gas delivery control signal, and/or a liquid delivery control signal, which are similar to those described with respect to FIG. 4B , and thus relevant details will not be repeated for simplicity.
- FIG. 4D Shown there is a relative position among the stage positioning module 516 , the beam splitter 605 at the sidewall 4155 of the wafer stage 415 , the sensor 520 ( 522 ), and the sensor 615 .
- the stage positioning module 516 may be used to measure the position of the wafer stage 415 .
- the stage positioning module 516 may emit a laser beam LB 3 toward the wafer stage 415 , such that the laser beam LB 3 is incident on an incident surface of the beam splitter 603 .
- the laser beam LB 3 is split, by the beam splitter 605 , into a laser beam LB 31 and a laser beam LB 32 , in which the laser beam LB 31 is the laser beam reflected by the beam splitter 605 , while the laser beam LB 32 is the laser beam transmitting through the beam splitter 605 .
- the laser beam LB 31 is reflected by the beam splitter 605 , and is directed upwardly to the sensor 520 ( 522 ).
- the laser beam LB 3 can be referred to as an incident laser beam
- the laser beam LB 31 can be referred to as a reflected laser beam
- the laser beam LB 32 can be referred to as a transmitted laser beam, respectively.
- the stage positioning module 516 can measure the position of the wafer stage 415 along the third direction (e.g., Z direction). For example, the stage positioning module 516 can emit the laser beam LB 3 toward the beam splitter 605 on the wafer stage 415 , the sensor 520 ( 522 ) above the wafer stage 415 can receive the reflected laser beam LB 31 from the beam splitter 605 , and therefore calculate the distance between the sensor 520 ( 522 ) and the beam splitter 605 , which determines the position of the wafer stage 415 .
- the sensor 520 ( 522 ) is optically coupled to the stage positioning module 516 through the beam splitter 605 .
- the stage positioning module 516 is able to send a control signal to control the wafer stage 415 .
- the stage positioning module 516 can emit the laser beam LB 3 toward the beam splitter 605 on the wafer stage 415 , while the laser beam LB 3 can be a modulated laser, which carries a control signal.
- the sensor 615 in the wafer stage 415 can receive the transmitted laser beam LB 32
- the processor 620 can decode the transmitted laser beam LB 32 to obtain the control signal carried by the transmitted laser beam LB 32 .
- the sensor 615 is optically coupled to the stage positioning module 516 through the beam splitter 605 .
- the processor 620 can transmit the control signal to the controller 630 , and the controller 630 can control the wafer stage 415 in several manners.
- the controller 630 may control the wafer stage 415 , according to the control signal carried by the laser beam LB 3 , the position of the wafer stage 415 , the delivery of gas from the gas sources 502 , 504 (see FIG. 3A ), and the delivery of liquid from the liquid source 506 (see FIG. 3A ).
- the control signal may be a position control signal, a gas delivery control signal, and/or a liquid delivery control signal, which are similar to those described with respect to FIG. 4B , and thus relevant details will not be repeated for simplicity.
- a wireless control operation is provided to control a wafer stage by emitting a modulated laser beam, which carries a control signal, toward a beam splitter on a wafer stage, the modulated laser beam may transmit through the beam splitter and may be received by a sensor in the wafer stage. Accordingly, processor and controller in the wafer stage are able to control the wafer stage according to the received control signal.
- a cable for transmitting control signal can be omitted, which will reduce about 30% to about 40% number of the cables (such as cables 440 A to 440 D in FIGS. 3A and 3B ). As a result, less cables will cause less particles (such as dust) falling on the table body, and will further reduce particle defect on the wafer, which in turn will improve die yield.
- FIG. 5 illustrates a method M 1 of operating a lithography system in accordance with some embodiments of the present disclosure.
- FIGS. 6A to 6C are schematic views of a lithography system in various stages of operations of method M 1 .
- the method M 1 is illustrated and/or described as a series of acts or events, it will be appreciated that the method is not limited to the illustrated ordering or acts. Thus, in some embodiments, the acts may be carried out in different orders than illustrated, and/or may be carried out concurrently. Further, in some embodiments, the illustrated acts or events may be subdivided into multiple acts or events, which may be carried out at separate times or concurrently with other acts or sub-acts.
- FIGS. 6A to 6C have been described in FIGS. 3A to 3B and 4A to 4D , such elements are labeled the same and relevant details will not be repeated for simplicity.
- the method M 1 starts at operation S 101 , a wafer stage is moved to a first station of a lithography system. As shown in FIG. 6A , the wafer stage 415 is moved to the first station ST 1 of the lithography chamber 400 , such that the wafer stage 415 is below an alignment sensor 530 . In some embodiments, the wafer stage 415 can be moved by, for example, emitted one or more modulated laser beams from the stage positioning modules 510 , 512 , 514 , and/or 516 .
- the modulated laser beams which carries a position control signal, can be the laser beam LB 1 of FIG. 4B , the laser beam LB 2 of FIG.
- the modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as the beam splitters 604 , 603 , and/or 605 of FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as the sensors 614 , 613 , and/or 615 of FIGS. 4A to 4D ).
- the processor in the wafer stages 415 (such as the processor 620 of FIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as the controller 630 of FIGS. 4A to 4D ). As a result, the controller can control the first sliding member 420 and the second sliding member 430 to move the wafer stage 415 to the first station ST 1 .
- the method M 1 proceeds to operation S 102 , a cleaning process and a purging process are performed.
- a cleaning process may be performed by ejecting a hydrogen (H 2 ) gas from a top surface 4151 of the wafer stage 415 to blow particles away from the wafer stage 415
- a purging process may be performed by ejecting an extreme clean dry air (XCDA) to purge the hydrogen (H 2 ) gas of the cleaning process.
- XCDA extreme clean dry air
- the cleaning process can be done by, for example, emitted one or more modulated laser beams from the stage positioning modules 510 , 512 , 514 , and/or 516 .
- the modulated laser beams which carries a gas delivery control signal, can be the laser beam LB 1 of FIG. 4B , the laser beam LB 2 of FIG. 4C , and/or the laser beam LB 3 of FIG. 4D .
- the modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as the beam splitters 604 , 603 , and/or 605 of FIGS.
- the processor in the wafer stages 415 may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as the controller 630 of FIGS. 4A to 4D ).
- the controller can turn on a valve of the cable 440 A connected to the gas source 502 to introduce the gas from the gas source 502 (e.g., H 2 ) into the wafer stage 415 , and then ejecting the gas out of the wafer stage 415 to clean the wafer stage 415 , such as blowing particle away from top surface 4151 of the wafer stage 415 .
- the gas source 502 e.g., H 2
- the purging process can be done by, for example, emitted one or more modulated laser beams from the stage positioning modules 510 , 512 , 514 , and/or 516 .
- the modulated laser beams which carries a gas delivery control signal, can be the laser beam LB 1 of FIG. 4B , the laser beam LB 2 of FIG. 4C , and/or the laser beam LB 3 of FIG. 4D .
- the modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as the beam splitters 604 , 603 , and/or 605 of FIGS.
- the processor in the wafer stages 415 may decode the modulated laser beams to transmit the control signal to the controller in the wafer stages 415 (such as the controller 630 of FIGS. 4A to 4D ).
- the controller can turn on a valve of the cable 440 B connected to the gas source 504 to introduce the gas from the gas source 504 (e.g., XCDA) into the wafer stage 415 , and then ejecting the gas out of the wafer stage 415 to purge the gas from the gas source 502 (e.g., H 2 ) away.
- the gas source 504 e.g., XCDA
- H 2 purge the gas from the gas source 502
- the method M 1 proceeds to operation S 103 , a wafer is placed on the wafer stage and an alignment process is performed.
- a wafer W is placed on the top surface 4151 of the wafer stage 415 .
- a robot arm e.g., the robot arm 269 in FIG. 2
- the alignment process may include measuring alignment marks provided on the wafer W, detecting an exact position of the wafer stage 415 , and measuring an exact location of the alignment marks on the wafer W.
- an alignment sensor 530 at the first station ST 1 can measure alignment marks provided on the wafer W.
- an exact position of the wafer stage 415 is detected by the stage positioning modules 510 , 512 , and 516 , and the sensors 520 . By comparing the exact position of the wafer stage 415 and the measurement performed by the alignment sensor 530 , the exact location of the alignment mark on the wafer W can be measured.
- the exact position of the wafer stage 415 may be detected by the method as described with respect to FIGS. 4A to 4D .
- laser beams may be emitted from the stage positioning modules 510 , 512 , and 516 .
- the laser beams may be reflected by the respective beam splitters on the wafer stages 415 (such as the beam splitters 604 , 603 , and/or 605 of FIGS. 4A to 4D ), and the reflected laser beams may be received by the respective sensors, such as the sensors in the stage positioning modules 510 , 512 , or the sensor 520 over the wafer stage 415 . Accordingly, the position of the wafer stage 415 may be detected.
- the method M 1 proceeds to operation S 104 , the wafer stage is moved to a second station of the lithography system. As shown in FIG. 6C , the wafer stage 415 is moved to the second station ST 2 of the lithography chamber 400 , such that the wafer stage 415 is below the projection system 532 . In some embodiments, the wafer stage 415 can be moved by, for example, emitted one or more modulated laser beams from the stage positioning modules 510 , 512 , 514 , and/or 516 .
- the modulated laser beams which carries a position control signal, can be the laser beam LB 1 of FIG. 4B , the laser beam LB 2 of FIG.
- the modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as the beam splitters 604 , 603 , and/or 605 of FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as the sensors 614 , 613 , and/or 615 of FIGS. 4A to 4D ).
- the processor in the wafer stages 415 (such as the processor 620 of FIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as the controller 630 of FIGS. 4A to 4D ). As a result, the controller can control the first sliding member 420 and the second sliding member 430 to move the wafer stage 415 and the wafer W to the second station ST 2 .
- the method M 1 proceeds to operation S 105 , a lithography process is performed.
- an exposure process may be performed, by the projection system 532 , to a layer of photoresist disposed on the wafer W, so as to pattern the layer of photoresist on the wafer W.
- a cooling process is performed.
- a cooling process may be performed to the wafer stage after the lithography process.
- the cooling process can be done by, for example, emitted one or more modulated laser beams from the stage positioning modules 510 , 514 , and/or 516 .
- the modulated laser beams which carries a liquid delivery control signal, can be the laser beam LB 1 of FIG. 4B , the laser beam LB 2 of FIG. 4C , and/or the laser beam LB 3 of FIG. 4D .
- the modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as the beam splitters 604 , 603 , and/or 605 of FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as the sensors 614 , 613 , and/or 615 of FIGS. 4A to 4D ).
- the processor in the wafer stages 415 (such as the processor 620 of FIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as the controller 630 of FIGS. 4A to 4D ).
- the controller can turn on a valve of the cable 440 C connected to the liquid source 506 to introduce the liquid from the liquid source 506 (e.g., water) into the wafer stage 415 , so as to cool down the wafer stages 415 .
- the liquid source 506 e.g., water
- a wireless control method is provided to control a wafer stage by emitting a modulated laser beam, which carries a control signal, toward a beam splitter on a wafer stage, the modulated laser beam may transmit through the beam splitter and may be received by a sensor in the wafer stage. Accordingly, processor and controller in the wafer stage are able to control the wafer stage according to the received control signal.
- a cable for transmitting control signal can be omitted, which will reduce about 30% to about 40% number of the cables. As a result, less cables will cause less particles (such as dust) falling on the table body, and will further reduce particle defect on the wafer, which in turn will improve die yield.
- a method includes moving a wafer stage to a first station on a table body of a lithography chamber; placing a wafer on a top surface of the wafer stage; emitting a first laser beam from a first laser emitter toward a first beam splitter on a first sidewall of the wafer stage, wherein a first portion of the first laser beam is reflected by the first beam splitter to form a first reflected laser beam, and a second portion of the first laser beam transmits through the first beam splitter to form a first transmitted laser beam; calculating a position of the wafer stage on a first axis based on the first reflected laser beam; after calculating the position of the wafer, moving the wafer stage to a second station on the table body; and performing a lithography process to the wafer when the wafer stage is at the second station.
- calculating the position of the wafer stage on the first axis comprises receiving the first reflected laser beam by a sensor adjacent to the first laser emitter.
- the method further includes emitting a second laser beam from a second laser emitter toward a second beam splitter on a second sidewall of the wafer stage, in which a first portion of the second laser beam is reflected by the second beam splitter to form a second reflected laser beam, and a second portion of the second laser beam transmits through the second beam splitter to form a second transmitted laser beam, and in which an incident surface of the second beam splitter is tiled about 45° relative to a top surface of the table body; and based on the second reflected laser beam, calculating the position of the wafer stage on a second axis perpendicular to the first axis.
- an incident surface of the first beam splitter is substantially vertical to the top surface of the table body.
- calculating the position of the wafer stage on the second axis comprises receiving the second reflected laser beam by a sensor disposed above the wafer stage.
- moving the wafer stage to the second station on the table body includes: when the wafer stage is at the first station, emitting a modulated laser beam, which carries a position control signal, from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving the modulated laser beam transmitting through the first beam splitter by a sensor in the wafer stage; and based on the position control signal carried by the received modulated laser beam, moving the wafer stage.
- the method further includes emitting a modulated laser beam, which carries a gas delivery control signal, from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving the modulated laser beam transmitting through the first beam splitter by a sensor in the wafer stage; and based on the gas delivery control signal carried by the received modulated laser beam, ejecting a gas out of the wafer stage.
- the method further includes emitting a modulated laser beam, which carries a liquid delivery control signal, from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving the modulated laser beam transmitting through the first beam splitter by a sensor in the wafer stage; and based on the liquid delivery control signal carried by the received modulated laser beam, introducing a liquid into the wafer stage.
- a method includes moving a wafer stage to a first station on a table body of a lithography chamber; placing a wafer on a top surface of the wafer stage; emitting a first modulated laser beam from a first laser emitter toward a first beam splitter on a first sidewall of the wafer stage; receiving a first portion of the first modulated laser beam transmitting through the first beam splitter by a first sensor in the wafer stage; in response to the received first portion of the first modulated laser beam, moving the wafer stage from the first station to a second station on the table body; and performing a lithography process to the wafer when the wafer stage is at the second station.
- the method further includes emitting a first unmodulated laser beam from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving, by the first stage positioning module, a second portion of the first unmodulated laser beam reflected by the first beam splitter; and calculating a position of the wafer stage on a first axis based on the received second portion of the first unmodulated laser beam.
- the method further includes emitting a second unmodulated laser beam from a second laser emitter toward a second beam splitter on a second sidewall of the wafer stage; receiving, by a second sensor above the wafer stage, a portion of the second unmodulated laser beam reflected by the second beam splitter; and calculating the position of the wafer stage on a second axis.
- an incident surface of the first beam splitter is substantially vertical to the top surface of the wafer stage, and an incident surface of the second beam splitter is tilted about 45° relative to the top surface of the wafer stage.
- the method further includes emitting a second modulated laser to the first sensor in the wafer stage through the first beam splitter on the first sidewall of the wafer stage; and in response to the second modulated laser, ejecting a hydrogen gas out of the wafer stage, in which the wafer is placed on the wafer stage after the step of ejecting the hydrogen gas is complete.
- the method further includes emitting a third modulated laser to the first sensor in the wafer stage through the first beam splitter on the first sidewall of the wafer stage; and in response to the third modulated laser, ejecting a dry air out of the wafer stage.
- the method further includes after the lithography process is complete, emitting a fourth modulated laser to the first sensor in the wafer stage through the first beam splitter on the first sidewall of the wafer stage; and in response to the fourth modulated laser, introducing a water into the wafer stage by emitting a fourth modulated laser.
- a method includes moving a wafer stage to a first station on a table body of a lithography chamber; placing a wafer on a top surface of the wafer stage; determining a position of the wafer stage by a wireless operation that comprises emitting a first laser beam from a first laser emitter to a first sensor inside the wafer stage through a first beam splitter on a first sidewall of the wafer stage; and after determining the position of the wafer stage by the wireless operation, performing a lithography process to the wafer using a projection system above the wafer stage.
- an incident surface of the first beam splitter is substantially vertical to a top surface of the table body.
- an incident surface of the first beam splitter is tilted about 45° relative to a top surface of the table body.
- determining the position of the wafer stage by the wireless operation further comprises emitting a second laser beam from a second laser emitter to a second sensor above the wafer stage through a second beam splitter on a second sidewall of the wafer stage adjacent to the first sidewall of the wafer stage; and emitting a third laser beam from a third laser emitter to a third sensor inside the wafer stage through a third beam splitter on a third sidewall of the wafer stage opposite to the second sidewall of the wafer stage.
- the method further includes, after the lithography process is complete, introducing water into the wafer stage through a cable connected to a fourth sidewall of the wafer stage opposite to the first sidewall of the wafer stage.
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Abstract
Description
- The present application claims priority to U.S. Provisional Application Ser. No. 63/181,879, filed Apr. 29, 2021, which is herein incorporated by reference.
- The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of IC processing and manufacturing. For these advances to be realized, similar developments in IC processing and manufacturing are needed. For example, the need to perform higher resolution lithography processes grows. One lithography technique is extreme ultraviolet lithography (EUVL). Other techniques include X-Ray lithography, ion beam projection lithography, electron beam projection lithography, and multiple electron beam maskless lithography.
- Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
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FIG. 1 is a schematic view of a lithography system in accordance with some embodiments of the present disclosure. -
FIG. 2 is a schematic view of a lithography system in accordance with some embodiments of the present disclosure. -
FIGS. 3A and 3B are a schematic view of a wafer table of a lithography chamber in accordance with some embodiments of the present disclosure. -
FIG. 4A is a schematic view of a wafer stage of a lithography chamber in accordance with some embodiments of the present disclosure. -
FIG. 4B toFIG. 4D are partial views of the wafer stage ofFIG. 4A in accordance with some embodiments of the present disclosure. -
FIG. 5 illustrates a method of operating a lithography system in accordance with some embodiments of the present disclosure. -
FIGS. 6A to 6C are schematic views of a lithography chamber in various stages of operations in accordance with some embodiments of the present disclosure. - The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
- Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
- The advanced lithography process, method, and materials described in the current disclosure can be used in many applications, including fin-type field effect transistors (FinFETs). For example, the fins may be patterned to produce a relatively close spacing between features, for which the above disclosure is well suited. In addition, spacers used in forming fins of FinFETs can be processed according to the above disclosure.
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FIG. 1 is a schematic view of lithography system in accordance with some embodiments of the present disclosure. Shown there is aEUV lithography system 10. Although theEUV lithography system 10 is illustrated as having a certain configuration of components, it will be appreciated that the disclosedlithography system 10 may include additional components (e.g., additional mirrors) or having less components (e.g., less mirrors). - The EUV
lithography system 10 includes aEUV source vessel 110. Afuel droplet generator 120 is connected to the EUVsource vessel 110 and is configured to generate a plurality offuel droplets 112. In some embodiments, thefuel droplets 112 generated by thefuel droplet generator 120 are provided into the EUVsource vessel 110. In some embodiments, thefuel droplets 112 may include tin (Sn). In other embodiments, thefuel droplets 112 may include a different metal material. In some embodiments, the EUVsource vessel 110 can also be referred to as a radiation source, in which radiation source employs a laser produced plasma (LPP) mechanism to generate plasma and further generate EUV light from the plasma. - The EUV
lithography system 10 may also include a droplet position detection system which may include adroplet imager 140 disposed in the EUVsource vessel 110 that captures an image of one ormore fuel droplets 112. Thedroplet imager 140 may provide this captured image to a droplet position detection feedback system (not shown), which can, e.g., generate a droplet position and trajectory in response to an analysis result of the captured image. The position detection feedback system can thus generate a droplet error in response to the generated droplet position and trajectory, e.g., based on a droplet-by-droplet basis, or on average. In some embodiments, thedroplet imager 140 may include a fine droplet steering camera (FDSC), a droplet formation camera (DFC), and/or suitable devices. - The EUV
lithography system 10 further includes a primary laser having alaser source 102 configured to produce alaser beam 104. In some embodiments, thelaser source 102 may include a multi-stage laser having a plurality of stages configured to amplify laser light produced by a prior stage. Thelaser beam 104 passes through abeam transport system 106 configured to provide the laser beam to a focusingsystem 108. The focusingsystem 108 includes one ormore lenses laser beam 104. Thelaser beam 104 is output from the focusingsystem 108 to the EUVsource vessel 110. - The
laser beam 104 transmits through acollector mirror 118 located within theEUV source vessel 110. Then, theprimary laser beam 104 generated by thelaser source 102 intersects thefuel droplets 112. In some embodiments, theprimary laser beam 104 may be a carbon dioxide (CO2) laser. In other embodiments, theprimary laser beam 104 may include alternative types of lasers. When theprimary laser beam 104 strikes thefuel droplets 112, theprimary laser beam 104 heats thefuel droplets 112 to a predetermined temperature. At the predetermined temperature, thefuel droplets 112 shed their electrons and become aplasma 114 including a plurality of ions. In some embodiments, the ions emit EUV radiation 116 (e.g., having a wavelength of approximately 13.3 nm to about 13.7 nm). - In some embodiments, the
collector mirror 118 has a concave curvature. In some embodiments, thecollector mirror 118 may include a multi-layer coating having alternating layers of different materials. For example, in some embodiments, the collector mirror 218 may include alternating layers of molybdenum and silicon configured to operate as a Bragg reflector. The concave curvature of the collector mirror 218 focuses theEUV radiation 116 generated by theplasma 114 toward an intermediate focus (IF)unit 130 within an exit aperture of theEUV source vessel 110. Theintermediate focus unit 130 is located between theEUV source vessel 110 and ascanner 200 including optical elements configured to direct theEUV radiation 116 to a workpiece (e.g., a semiconductor substrate). In some embodiments, theintermediate focus unit 130 may include a cone shaped aperture configured to provide for separation of pressures between theEUV source vessel 110 and thescanner 200. In some embodiments, theintermediate focus unit 130 may extend into thescanner 200. - The
EUV lithography system 10 may also include an EUV energy monitor 150 disposed in theEUV source vessel 110. TheEUV energy monitor 150 is designed to monitor the EUV intensity or energy generated from theEUV source vessel 110. For example, theEUV energy monitor 150 includes an EUV sensing element, such as a diode, designed to be sensitive to the EUV light and configured to effectively detect the EUV light. In other examples, theEUV energy monitor 150 includes a plurality of diodes configured in an array to effectively detect the EUV light for monitoring purpose. In some embodiments, a dose error is calculated based on the sensed EUV intensity (or energy). For example, when the sensed EUV intensity (or energy) is below a predetermined threshold value, such situation can be referred to as a dose error. Generally, the dose error is related to the plasma instability, through monitoring the EUV intensity by theEUV energy monitor 150, the dose error can be extracted from the monitored EUV intensity. Therefore, when a dose error is occurred, it indicates that theplasma 114 is unstable. - In some embodiments, the EUV lithography system further includes a
droplet collection element 125 disposed in theEUV source vessel 110 and located opposite to thedroplet generator 120. Thedroplet collection element 125 is configured to collectfuel droplets 112 that are not vaporized during formation of theEUV radiation 116 and/or fragments offuel droplets 112 generated during formation of theEUV radiation 116. - The
EUV radiation 116 output from theEUV source vessel 110 is provided to acondenser 210 by way of theintermediate focus unit 130. In some embodiments, thecondenser 210 includes first andsecond surfaces EUV radiation 116, and areflector 214 configured to reflect theEUV radiation 116 towards anEUV photomask 220. TheEUV photomask 220 is configured to reflect theEUV radiation 116 to form a pattern on a surface of asemiconductor wafer 250. To produce the pattern, theEUV photomask 220 may include a plurality ofabsorptive features EUV photomask 220. The plurality ofabsorptive features EUV radiation 116, such that the reflected rays ofEUV radiation 116 conveys a patterned defined by theEUV photomask 220. - The
EUV radiation 116 is filtered through reduction optics including a series of first tofourth mirrors EUV radiation 116. In some embodiments, thefourth mirror 230 d is the last mirror that directly reflects theEUV radiation 116 from previous mirrors onto a on a layer of photoresist coated on a surface of thesemiconductor wafer 250. TheEUV radiation 116 irradiates particular regions of the layer of photoresist based on the pattern carried by theEUV radiation 116, and thus the layer of irradiated photoresist layer can be patterned after developing it. Therefore, subsequent processing can be performed on selected regions of thesemiconductor wafer 250. -
FIG. 2 is a schematic view of alithography system 20 according to the present disclosure. Thelithography system 20 may be applied to pattern semiconductor wafers, as discussed above with respect to thesemiconductor wafer 250 ofFIG. 1 . Here, thewafers 250 are indicated by dashed circles. Generally, the wafers are moved from awafer handler 260, throughload locks wafer exchange chamber 266, to alithography chamber 271. It is understood that the lithography process discussed inFIG. 1 is performed when thewafer 250 is positioned in thelithography chamber 271. In some embodiments, prior to performing the lithography process, thewafers 250 in thewafer handler 260 may have been undergone several processes, such as resist-apply, pre-bake, and other processes . . . etc. After the lithography process, wafers are returned to thewafer handler 260 for further processing steps, such as development, post bake, and the like. - The
wafer handler 260 is separated from the load locks 264, 264 bygate valve assemblies wafer exchange chamber 266 bygate valve assemblies wafer handler 260 and thewafer exchange chamber 266 by respectivegate valve assemblies wafer exchange chamber 266 can be held at a high vacuum whilewafer handler 260 is held at atmospheric pressure. The load locks 264, 265 thus serve to move wafers in and out from thewafer exchange chamber 266 while transitioning from atmospheric pressure to high vacuum. - In some embodiments, the
wafer exchange chamber 266 may include arobot arm 269. Therobot arm 269 is used to transfer wafers from the load locks 264, 265 to thelithography chamber 271. In some embodiments, therobot arm 269 may include a single end-effector, or dual, non-robotic, transport mechanisms could also be used without departing from the scope of the present disclosure. - The
wafer exchange chamber 266 is connected tolithography chamber 271 through agate valve assembly 270. In some embodiments, thelithography chamber 271 includes wafer stages 272, 273. The wafer stages 272, 273 are capable of movement in the directions indicated for fine alignment and exposure processes. Thelithography chamber 271 thus further includes projection optics or other elements necessary to perform the lithography patterning. Whilelithography chamber 271 is illustrated to have twowafer stages -
FIGS. 3A and 3B illustrate different views of a wafer table of a lithography chamber in accordance with some embodiments of the present disclosure. It is noted that thelithography chamber 400 discussed inFIGS. 3A and 3B is similar to thelithography chamber 271 discussed inFIG. 2 . - The
lithography chamber 400 includes a table body 410 (e.g., stage frame). Thetable body 410 includes atop surface 4101, asidewall 4102, asidewall 4103, asidewall 4104, and asidewall 4105. Thesidewall 4102 is connected to thesidewalls sidewall 4104. Thesidewall 4103 is connected to thesidewalls sidewall 4105. Thesidewall 4104 is connected to thesidewalls sidewall 4102. Thesidewall 4105 is connected to thesidewalls sidewall 4103. - At least one
wafer stage 415 is movably disposed on thetable body 410, in which thetable body 410 may include a flat, leveltop surface 4101 over which thewafer stage 415 can move. A wafer W may be disposed on atop surface 4151 of thewafer stage 415. It is noted that, thewafer stage 415 here can be similar to the wafer stages 272, 273 discussed inFIG. 2 . In some embodiments, thewafer stage 415 may be coupled to thetable body 410 in a non-contact manner. For example, thetable body 410 may include a magnet array (stator) of a planar motor while the coil units are built inside thewafer stage 415, so that thewafer stage 415 can be suspended above the table body by using magnetic levitation. In greater detail, thewafer stage 415 can be suspended above thetable body 410 with no support other than magnetic field generated from thetable body 410, and the magnetic force can be used to counteract the effects of gravitational acceleration. In this way, thewafer stage 415 can be horizontally moved above thetable body 410 without contacting thetable body 410. In some embodiments, thewafer stage 415 is supported by magnetic levitation above thetable body 410 in a non-contact manner by a predetermined clearance, such as around several μm, by adjusting the balance of the upward force (repulsion) such as the electromagnetic force and the downward force (gravitation) including the self-weight, and is also finely driven at least in directions of two degrees of freedom, which are the X-axis direction and the Y-axis direction by using a driving mechanism. In some embodiments, the electromagnetic force can be controlled to raise or lower thewafer stage 415, so that thewafer stage 415 have an additional degree of freedom on the Z-axis direction as well. - The
wafer stage 415 includes atop surface 4151, asidewall 4152, asidewall 4153, asidewall 4154, and asidewall 4155. Thesidewall 4152 is connected to thesidewalls sidewall 4154. Thesidewall 4153 is connected to thesidewalls sidewall 4155. Thesidewall 4154 is connected to thesidewalls sidewall 4152. Thesidewall 4155 is connected to thesidewalls sidewall 4153. In some embodiments, thesidewalls wafer stage 415 are substantially vertical to thetop surface 4101 of thetable body 410. On the other hand, thesidewall 4155 is an inclined surface, which is tilted about 45° relative to thetop surface 4101 of thetable body 410. Stated another way, thesidewall 4155 forms an angle about 45° with thetop surface 4101 of thetable body 410. - In some embodiments, the
wafer stage 415 is horizontally movable between a first station ST1 and a second station ST2 of thetable body 410. The horizontal motion can be controlled by a motor coupled to thewafer stage 415, and a range of horizontal motion is sufficient to transfer thewafer stage 415 from the first station ST1 to the second station ST2, and also sufficient to transfer thewafer stage 415 from the second station ST2 to the first station ST1. Thelithography chamber 400 includes analignment sensor 530 above thewafer stage 415. In some embodiments, when thewafer stage 415 is at the first station ST1, thealignment sensor 530 can measure alignment marks provided on the wafer W disposed on thewafer stage 415, such that the exact position of the wafer W can be measured, and therefore the wafer W can be properly aligned with a patterning device. When thewafer stage 415 is moved to the second station ST2 (e.g., seeFIG. 6C ), an exposure process can be performed to the wafer W disposed on thewafer stage 415 through aprojection system 532 above thewafer stage 415. In some embodiments, theprojection system 532 may include, for example, thecondenser 210 ofFIG. 1 , thephotomask 220 ofFIG. 1 , and themirrors 230 a to 230 d ofFIG. 1 , which are used to convey a radiation onto a layer of photoresist coated on the wafer W. For example, when thewafer stage 415 is at the second station ST2 (e.g., seeFIG. 6C ), an exposure process can be performed to a layer of photoresist coated on the wafer W, so as to pattern the layer of photoresist. Because the first station ST1 is serve to perform the alignment process and the second station ST2 is serve to perform the exposure process, the first station ST1 can be referred to as an alignment station, and the second station ST2 can be referred to as an exposure station. - The
lithography chamber 400 also includes a first slidingmember 420 and a second slidingmember 430, which are used to move thewafer stage 415 over thetop surface 4101 of thetable body 410. In some embodiments, the second slidingmember 430 has afirst portion 430A extending along thetop surface 4101 of thetable body 410, and asecond portion 430B on thesidewall 4102 of thetable body 410. In some embodiments, thesecond portion 430B of the second slidingmember 430 is coupled to aslot 412 on thesidewall 4102 of thetable body 410, such that the second slidingmember 430 can be movable along theslot 412 at thesidewall 4102 of thetable body 410 in a first direction (e.g., the X direction). - The second sliding
member 430 further includes atrack 432 coupled to thefirst portion 430A. Thetrack 432 extends along thetop surface 4101 of thetable body 410 and extends in a second direction (e.g., the Y direction). In some embodiments, the first slidingmember 420 is movably mounted on thetrack 432 of the second slidingmember 430, such that the first slidingmember 420 can be movable along thetrack 432 of the second slidingmember 430 in a second direction (e.g., the Y direction). - The first sliding
member 420 is further coupled to thewafer stage 415. As a result, thewafer stage 415 is also coupled to the second slidingmember 430 through the first slidingmember 420. Accordingly, with such configuration, thewafer stage 415 is movable over thetop surface 4101 of thetable body 410 along a plane (e.g., X-Y plane) constructed by the first direction (e.g., the X direction) and the second direction (e.g., the Y direction). For example, thewafer stage 415 can move along the first direction (e.g., the X direction) when the second slidingmember 430 is actuated to move along theslot 412 on thesidewall 4102 of thetable body 410, and can move along the second direction (e.g., the Y direction) when the first slidingmember 420 is actuated to move along thetrack 432 of the second slidingmember 430. - The
lithography chamber 400 further includes a plurality ofcables cables sidewall 4152 of thewafer stage 415. In some embodiments, thecable 440A is connected to agas source 502, thecable 440B is connected to agas source 504, thecable 440C is connected to a liquid source, and thecable 440D is connected to apower source 508. In some embodiments, thegas source 502 may be a hydrogen (H2) source, which provides hydrogen (H2) gas into thewafer stage 415. In some embodiments, thegas source 504 may be an extreme clean dry air (XCDA) source, which provides extreme clean dry air into thewafer stage 415. In some embodiments, theliquid source 506 may be a water (H2O) source, which provides water into thewafer stage 415. In some embodiments, thepower source 508 may be a power supplier, which provides electrical power to thewafer stage 415. -
Brackets 460 are configured to fix thecables 440A to 440D together, such that thecables 440A to 440D may be arranged neatly and in a desired order. Furthermore, thecable 440A to 440D may be movable along with each other. -
Gate valve assembly 450 is disposed close to thesidewall 4103 of thetable body 410. Thegate valve assembly 450 may be similar to thegate valve assembly 270 described inFIG. 2 . In some embodiments, a robot arm (e.g., therobot arm 269 ofFIG. 2 ) may transfer a wafer into thelithography chamber 400 through thegate valve assembly 450, and then place the wafer, such as the wafer W, on thewafer stage 415. It is noted that thegate valve assembly 450 is not illustrated inFIG. 3A for clarity. - The
lithography chamber 400 also includes a plurality ofstage positioning modules stage positioning module 510 is disposed at the side of thesidewall 4103 of thetable body 410. Thestage positioning modules sidewall 4104 of thetable body 410, and are spaced apart from each other along the first direction (e.g., X direction). Thestage positioning module 516 is disposed at the side of thesidewall 4105 of thetable body 410. - In some embodiments, the
stage positioning module 510 may include a laser emitter aimed at thesidewall 4153 of thewafer stage 415, and a sensor adjacent to the laser emitter. For example, the laser emitter of thestage positioning module 510 can emit a laser beam to thesidewall 4153 of thewafer stage 415. Thesidewall 4153 can reflect the laser beam back to thestage positioning module 510, such that the sensor adjacent to the laser emitter can measure the position of thewafer stage 415 along the first direction (e.g., X direction). - In some embodiments, the
stage positioning module 512 may include a laser emitter and a sensor adjacent to the laser emitter. When thewafer stage 415 is at the first station ST1, the laser emitter can be aimed at thesidewall 4154 of thewafer stage 415. For example, the laser emitter of thestage positioning module 512 can emit a laser beam to thesidewall 4154 of thewafer stage 415. Thesidewall 4154 can reflect the laser beam back to the sensor adjacent to the laser emitter, such that thestage positioning module 512 can measure the position of thewafer stage 415 along the second direction (e.g., Y direction) when thewafer stage 415 is at the first station ST1. - In some embodiments, the
stage positioning module 514 may include a laser emitter and a sensor adjacent to the laser emitter. When thewafer stage 415 is at the second station ST2, the laser emitter can be aimed at thesidewall 4154 of thewafer stage 415. Similarly, the laser emitter of thestage positioning module 514 can emit a laser beam to thesidewall 4154 of thewafer stage 415. Thesidewall 4154 can reflect the laser beam back to the sensor adjacent to the laser emitter, such that thestage positioning module 514 can measure the position of thewafer stage 415 along the second direction (e.g., Y direction) when thewafer stage 415 is at the second station ST2. - The
lithography chamber 400 also includes a plurality ofsensors table body 410. In some embodiments, when thewafer stage 415 is at the first station ST1, thesensor 520 is optically coupled to thestage positioning module 516. For example, thestage positioning module 516 may include a laser emitter aimed at thesidewall 4155 of thewafer stage 415. The laser emitter of thestage positioning module 516 can emit a laser beam to thesidewall 4155 of thewafer stage 415. Because thesidewall 4155 of thewafer stage 415 is tilted about 45° relative to thetop surface 4101 of thetable body 410, thesidewall 4155 of thewafer stage 415 can reflect the laser beam upwardly to thesensor 520, such that thesensor 520 and thestage positioning module 516 can collectively measure the position of thewafer stage 415 along a third direction (e.g., Z direction) when thewafer stage 415 is at the first station ST1. - When the
wafer stage 415 is at the second station ST2, thesensor 522 is optically coupled to thestage positioning module 516. Similarly, the laser emitter of thestage positioning module 514 can emit a laser beam to thesidewall 4155 of thewafer stage 415, and thesidewall 4155 of thewafer stage 415 can reflect the laser beam upwardly to thesensor 522, such that thesensor 522 and thestage positioning module 516 can collectively measure the position of thewafer stage 415 along the third direction (e.g., Z direction) when thewafer stage 415 is at the second station ST2. -
FIG. 4A is a schematic view of a wafer stage of a lithography chamber in accordance with some embodiments of the present disclosure.FIG. 4B toFIG. 4D are partial views of the wafer stage ofFIG. 4A in accordance with some embodiments of the present disclosure.FIG. 4A illustrates a detailed configuration of thewafer stage 415 discussed inFIGS. 3A and 3B , in which the perspective view of thewafer stage 415 inFIG. 4A is the same as the perspective view of thewafer stage 415 inFIG. 3B . - In some embodiments, the
sidewall 4153 of thewafer stage 415 includes abeam splitter 603, thesidewall 4154 of thewafer stage 415 includes abeam splitter 604, and thesidewall 4155 of thewafer stage 415 includes abeam splitter 605. However, thesidewall 4152 of thewafer stage 415 does not include a beam splitter. As mentioned above with respect toFIGS. 3A and 3B , thesidewall 4152 of thewafer stage 415 is connected to thecables 440A to 440D, and thus thesidewall 4152 of thewafer stage 415 may be made of a material different from a material of the beam splitter. - In some embodiments, the outer surfaces of the
beam splitters top surface 4101 of the table body 410 (seeFIGS. 3A and 3B ). In some embodiments, the surface of the outer surface of thebeam splitter 605 is tilted about 45° relative to thetop surface 4101 of the table body 410 (seeFIGS. 3A and 3B ). - The
wafer stage 415 includessensors wafer stage 415, in which a sensing surface of thesensor 613 faces thebeam splitter 603 at thesidewall 4153 of thewafer stage 415, a sensing surface of thesensor 614 faces thebeam splitter 604 at thesidewall 4154 of thewafer stage 415, and the sensing surface of thesensor 615 faces thebeam splitter 605 at thesidewall 4155 of thewafer stage 415. In some embodiments, the sensing surfaces of thesensors top surface 4101 of the table body 410 (seeFIGS. 3A and 3B ). In some embodiments, the sensing surfaces of thesensors beam splitters sidewalls wafer stage 415, respectively. On the other hand, the sensing surface of thesensor 615 is tilted about 45° relative to the outer surface of thebeam splitter 605 and thesidewall 4155 of thewafer stage 415. - The
wafer stage 415 includes aprocessor 620 electrically coupled to thesensors controller 630 electrically coupled to theprocessor 620. In some embodiments, theprocessor 620 can process the signal received from thesensors processor 620 and thecontroller 630 may include, for example, a central processing unit (CPU), a microprocessor, a programmable logic control unit, a computer or other device or system that is adapted to perform the functions described herein. - Reference is made to
FIG. 4B . Shown there is a relative position among the stage positioning module 512 (or 514), thebeam splitter 604 at thesidewall 4154 of thewafer stage 415, and thesensor 614. As mentioned above, the stage positioning module 512 (or 514) may be used to measure the position of thewafer stage 415. During measuring the position of thewafer stage 415, the stage positioning module 512 (or 514) may emit a laser beam LB1 toward thewafer stage 415, such that the laser beam LB1 is incident on an incident surface of thebeam splitter 604. As a result, the laser beam LB1 is split, by thebeam splitter 604, into a laser beam LB11 and a laser beam LB12, in which the laser beam LB11 is the laser beam reflected by thebeam splitter 604, while the laser beam LB12 is the laser beam transmitting through thebeam splitter 604. In some embodiments, the laser beam LB1 can be referred to as an incident laser beam, the laser beam LB11 can be referred to as a reflected laser beam, and the laser beam LB12 can be referred to as a transmitted laser beam, respectively. - As mentioned above, the stage positioning module 512 (or 514) can measure the position of the
wafer stage 415 along the second direction (e.g., Y direction). For example, the stage positioning module 512 (or 514) can emit the laser beam LB1 toward thebeam splitter 604 on thewafer stage 415, receive the reflected laser beam LB11 from thebeam splitter 604, and therefore calculate the distance between the stage positioning module 512 (or 514) and thebeam splitter 604, which determines the position of thewafer stage 415. - Furthermore, the stage positioning module 512 (or 514) is able to send a control signal to control the
wafer stage 415. For example, the stage positioning module 512 (or 514) can emit the laser beam LB1 toward thebeam splitter 604 on thewafer stage 415. The laser beam LB1 can be a modulated laser beam, which carries a control signal capable of triggering electrical and/or mechanical operations such as wafer stage movement/gas ejection/liquid ejection. By contrast, a laser beam that does not carry any control signal is called an unmodulated laser beam, such as the laser beam used to measure position of thewafer stage 415 as discussed previously. As a result, thesensor 614 in thewafer stage 415 can receive the transmitted laser beam LB12, and theprocessor 620 can decode the transmitted laser beam LB12 to obtain the control signal carried by the transmitted laser beam LB12. Thesensor 614 is optically coupled to the stage positioning module 512 (or 514) through thebeam splitter 604. - The
processor 620 further transmits the control signal to thecontroller 630, and thecontroller 630 can control thewafer stage 415 in several manners. In some embodiments, thecontroller 630 may control thewafer stage 415, according to the control signal carried by the laser beam LB1, the position of thewafer stage 415, the delivery of gas from thegas sources 502, 504 (seeFIG. 3A ), and the delivery of liquid from the liquid source 506 (seeFIG. 3A ). - For example, when the control signal is a position control signal, the
controller 630 can actuate the first slidingmember 420 and the second sliding member 430 (seeFIGS. 3A and 3B ), so as to move thewafer stage 415 to a desired position over thetable body 410, such as moving thewafer stage 415 to the first station ST1 or to the second station ST2 (seeFIGS. 3A and 3B ). During moving thewafer stage 415, the position of thewafer stage 415 can be detected simultaneously by detecting the reflected laser beam LB11. - Moreover, when the control signal is a gas delivery control signal, the
controller 630 can control a gas delivery to thewafer stage 415. In some embodiments, thegas source 502 may be a hydrogen (H2) source, and thegas source 504 may be an extreme clean dry air (XCDA) source. For example, thecontroller 630 may carry out a cleaning process by turning on a valve of thecable 440A connected to thegas source 502 to introduce the gas from the gas source 502 (e.g., H2) into thewafer stage 415, and then ejecting the gas out of thewafer stage 415 to clean thewafer stage 415, such as blowing particle away fromtop surface 4151 of thewafer stage 415. After the cleaning process, thecontroller 630 may further carry out a purging process by turning on a valve of thecable 440B connected to thegas source 504 to introduce the gas from the gas source 504 (e.g., XCDA) into thewafer stage 415, and then ejecting the gas out of thewafer stage 415 to purge the gas from the gas source 502 (e.g., H2) away. - Furthermore, when the control signal is a liquid delivery control signal, the
controller 630 can control a liquid delivery to thewafer stage 415. In some embodiments, theliquid source 506 may be a water source. For example, thecontroller 630 may carry out a cooling process by turning on a valve of thecable 440C connected to theliquid source 506 to introduce the liquid from the liquid source 506 (e.g., water) into thewafer stage 415. In some embodiments, the cooling process may be performed after performing an exposure process to a wafer. - Reference is made to
FIG. 4C . Shown there is a relative position among thestage positioning module 510, thebeam splitter 603 at thesidewall 4153 of thewafer stage 415, and thesensor 613. As mentioned above, thestage positioning module 510 may be used to measure the position of thewafer stage 415. During measuring the position of thewafer stage 415, thestage positioning module 510 may emit a laser beam LB2 toward thewafer stage 415, such that the laser beam LB2 is incident on an incident surface of thebeam splitter 603. As a result, the laser beam LB2 is split, by thebeam splitter 603, into a laser beam LB21 and a laser beam LB22, in which the laser beam LB21 is the laser beam reflected by thebeam splitter 603, while the laser beam LB22 is the laser beam transmitting through thebeam splitter 603. In some embodiments, the laser beam LB2 can be referred to as an incident laser beam, the laser beam LB21 can be referred to as a reflected laser beam, and the laser beam LB22 can be referred to as a transmitted laser beam, respectively. - As mentioned above, the
stage positioning module 510 can measure the position of thewafer stage 415 along the first direction (e.g., X direction). For example, thestage positioning module 510 can emit the laser beam LB2 toward thebeam splitter 603 on thewafer stage 415, receive the reflected laser beam LB21 from thebeam splitter 603, and therefore calculate the distance between thestage positioning module 510 and thebeam splitter 603, which determines the position of thewafer stage 415. - Furthermore, the
stage positioning module 510 is able to send a control signal to control thewafer stage 415. For example, thestage positioning module 510 can emit the laser beam LB2 toward thebeam splitter 603 on thewafer stage 415, while the laser beam LB2 can be a modulated laser, which carries a control signal. As a result, thesensor 613 in thewafer stage 415 can receive the transmitted laser beam LB22, theprocessor 620 can decode the transmitted laser beam LB22 to obtain the control signal carried by the transmitted laser beam LB22. Thesensor 613 is optically coupled to thestage positioning module 510 through thebeam splitter 603. - The
processor 620 further transmits the control signal to thecontroller 630, and thecontroller 630 can control thewafer stage 415 in several manners. In some embodiments, thecontroller 630 may control thewafer stage 415, according to the control signal carried by the laser beam LB2, the position of thewafer stage 415, the delivery of gas from thegas sources 502, 504 (seeFIG. 3A ), and the delivery of liquid from the liquid source 506 (seeFIG. 3A ). For example, the control signal may be a position control signal, a gas delivery control signal, and/or a liquid delivery control signal, which are similar to those described with respect toFIG. 4B , and thus relevant details will not be repeated for simplicity. - Reference is made to
FIG. 4D . Shown there is a relative position among thestage positioning module 516, thebeam splitter 605 at thesidewall 4155 of thewafer stage 415, the sensor 520 (522), and thesensor 615. As mentioned above, thestage positioning module 516 may be used to measure the position of thewafer stage 415. During measuring the position of thewafer stage 415, thestage positioning module 516 may emit a laser beam LB3 toward thewafer stage 415, such that the laser beam LB3 is incident on an incident surface of thebeam splitter 603. As a result, the laser beam LB3 is split, by thebeam splitter 605, into a laser beam LB31 and a laser beam LB32, in which the laser beam LB31 is the laser beam reflected by thebeam splitter 605, while the laser beam LB32 is the laser beam transmitting through thebeam splitter 605. It is understood that, the laser beam LB31 is reflected by thebeam splitter 605, and is directed upwardly to the sensor 520 (522). In some embodiments, the laser beam LB3 can be referred to as an incident laser beam, the laser beam LB31 can be referred to as a reflected laser beam, and the laser beam LB32 can be referred to as a transmitted laser beam, respectively. - As mentioned above, the
stage positioning module 516 can measure the position of thewafer stage 415 along the third direction (e.g., Z direction). For example, thestage positioning module 516 can emit the laser beam LB3 toward thebeam splitter 605 on thewafer stage 415, the sensor 520 (522) above thewafer stage 415 can receive the reflected laser beam LB31 from thebeam splitter 605, and therefore calculate the distance between the sensor 520 (522) and thebeam splitter 605, which determines the position of thewafer stage 415. The sensor 520 (522) is optically coupled to thestage positioning module 516 through thebeam splitter 605. - Furthermore, the
stage positioning module 516 is able to send a control signal to control thewafer stage 415. For example, thestage positioning module 516 can emit the laser beam LB3 toward thebeam splitter 605 on thewafer stage 415, while the laser beam LB3 can be a modulated laser, which carries a control signal. As a result, thesensor 615 in thewafer stage 415 can receive the transmitted laser beam LB32, theprocessor 620 can decode the transmitted laser beam LB32 to obtain the control signal carried by the transmitted laser beam LB32. Thesensor 615 is optically coupled to thestage positioning module 516 through thebeam splitter 605. - The
processor 620 can transmit the control signal to thecontroller 630, and thecontroller 630 can control thewafer stage 415 in several manners. In some embodiments, thecontroller 630 may control thewafer stage 415, according to the control signal carried by the laser beam LB3, the position of thewafer stage 415, the delivery of gas from thegas sources 502, 504 (seeFIG. 3A ), and the delivery of liquid from the liquid source 506 (seeFIG. 3A ). For example, the control signal may be a position control signal, a gas delivery control signal, and/or a liquid delivery control signal, which are similar to those described with respect toFIG. 4B , and thus relevant details will not be repeated for simplicity. - In some embodiments of the present disclosure, a wireless control operation is provided to control a wafer stage by emitting a modulated laser beam, which carries a control signal, toward a beam splitter on a wafer stage, the modulated laser beam may transmit through the beam splitter and may be received by a sensor in the wafer stage. Accordingly, processor and controller in the wafer stage are able to control the wafer stage according to the received control signal. With this configuration, a cable for transmitting control signal can be omitted, which will reduce about 30% to about 40% number of the cables (such as
cables 440A to 440D inFIGS. 3A and 3B ). As a result, less cables will cause less particles (such as dust) falling on the table body, and will further reduce particle defect on the wafer, which in turn will improve die yield. -
FIG. 5 illustrates a method M1 of operating a lithography system in accordance with some embodiments of the present disclosure.FIGS. 6A to 6C are schematic views of a lithography system in various stages of operations of method M1. Although the method M1 is illustrated and/or described as a series of acts or events, it will be appreciated that the method is not limited to the illustrated ordering or acts. Thus, in some embodiments, the acts may be carried out in different orders than illustrated, and/or may be carried out concurrently. Further, in some embodiments, the illustrated acts or events may be subdivided into multiple acts or events, which may be carried out at separate times or concurrently with other acts or sub-acts. In some embodiments, some illustrated acts or events may be omitted, and other un-illustrated acts or events may be included. It is noted that some elements ofFIGS. 6A to 6C have been described inFIGS. 3A to 3B and 4A to 4D , such elements are labeled the same and relevant details will not be repeated for simplicity. - Reference is made to
FIGS. 5 and 6A . The method M1 starts at operation S101, a wafer stage is moved to a first station of a lithography system. As shown inFIG. 6A , thewafer stage 415 is moved to the first station ST1 of thelithography chamber 400, such that thewafer stage 415 is below analignment sensor 530. In some embodiments, thewafer stage 415 can be moved by, for example, emitted one or more modulated laser beams from thestage positioning modules FIG. 4B , the laser beam LB2 ofFIG. 4C , and/or the laser beam LB3 ofFIG. 4D . The modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as thebeam splitters FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as thesensors FIGS. 4A to 4D ). The processor in the wafer stages 415 (such as theprocessor 620 ofFIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as thecontroller 630 ofFIGS. 4A to 4D ). As a result, the controller can control the first slidingmember 420 and the second slidingmember 430 to move thewafer stage 415 to the first station ST1. - Reference is still made to
FIGS. 5 and 6A . The method M1 proceeds to operation S102, a cleaning process and a purging process are performed. A cleaning process may be performed by ejecting a hydrogen (H2) gas from atop surface 4151 of thewafer stage 415 to blow particles away from thewafer stage 415, and a purging process may be performed by ejecting an extreme clean dry air (XCDA) to purge the hydrogen (H2) gas of the cleaning process. - In some embodiments, the cleaning process can be done by, for example, emitted one or more modulated laser beams from the
stage positioning modules FIG. 4B , the laser beam LB2 ofFIG. 4C , and/or the laser beam LB3 ofFIG. 4D . The modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as thebeam splitters FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as thesensors FIGS. 4A to 4D ). The processor in the wafer stages 415 (such as theprocessor 620 ofFIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as thecontroller 630 ofFIGS. 4A to 4D ). As a result, the controller can turn on a valve of thecable 440A connected to thegas source 502 to introduce the gas from the gas source 502 (e.g., H2) into thewafer stage 415, and then ejecting the gas out of thewafer stage 415 to clean thewafer stage 415, such as blowing particle away fromtop surface 4151 of thewafer stage 415. - The purging process can be done by, for example, emitted one or more modulated laser beams from the
stage positioning modules FIG. 4B , the laser beam LB2 ofFIG. 4C , and/or the laser beam LB3 ofFIG. 4D . The modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as thebeam splitters FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as thesensors FIGS. 4A to 4D ). The processor in the wafer stages 415 (such as theprocessor 620 ofFIGS. 4A to 4D ) may decode the modulated laser beams to transmit the control signal to the controller in the wafer stages 415 (such as thecontroller 630 ofFIGS. 4A to 4D ). As a result, the controller can turn on a valve of thecable 440B connected to thegas source 504 to introduce the gas from the gas source 504 (e.g., XCDA) into thewafer stage 415, and then ejecting the gas out of thewafer stage 415 to purge the gas from the gas source 502 (e.g., H2) away. - Reference is made to
FIGS. 5 and 6B . The method M1 proceeds to operation S103, a wafer is placed on the wafer stage and an alignment process is performed. InFIG. 6B , a wafer W is placed on thetop surface 4151 of thewafer stage 415. For example, a robot arm (e.g., therobot arm 269 inFIG. 2 ) may transfer the wafer W into thelithography chamber 400 through thegate valve assembly 450, and then place the wafer W over thewafer stage 415. - The alignment process may include measuring alignment marks provided on the wafer W, detecting an exact position of the
wafer stage 415, and measuring an exact location of the alignment marks on the wafer W. For example, analignment sensor 530 at the first station ST1 can measure alignment marks provided on the wafer W. Furthermore, an exact position of thewafer stage 415 is detected by thestage positioning modules sensors 520. By comparing the exact position of thewafer stage 415 and the measurement performed by thealignment sensor 530, the exact location of the alignment mark on the wafer W can be measured. - In some embodiments, the exact position of the
wafer stage 415 may be detected by the method as described with respect toFIGS. 4A to 4D . For example, laser beams may be emitted from thestage positioning modules beam splitters FIGS. 4A to 4D ), and the reflected laser beams may be received by the respective sensors, such as the sensors in thestage positioning modules sensor 520 over thewafer stage 415. Accordingly, the position of thewafer stage 415 may be detected. - Reference is made to
FIGS. 5 and 6C . The method M1 proceeds to operation S104, the wafer stage is moved to a second station of the lithography system. As shown inFIG. 6C , thewafer stage 415 is moved to the second station ST2 of thelithography chamber 400, such that thewafer stage 415 is below theprojection system 532. In some embodiments, thewafer stage 415 can be moved by, for example, emitted one or more modulated laser beams from thestage positioning modules FIG. 4B , the laser beam LB2 ofFIG. 4C , and/or the laser beam LB3 ofFIG. 4D . The modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as thebeam splitters FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as thesensors FIGS. 4A to 4D ). The processor in the wafer stages 415 (such as theprocessor 620 ofFIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as thecontroller 630 ofFIGS. 4A to 4D ). As a result, the controller can control the first slidingmember 420 and the second slidingmember 430 to move thewafer stage 415 and the wafer W to the second station ST2. - Reference is still made to
FIGS. 5 and 6C . The method M1 proceeds to operation S105, a lithography process is performed. In greater details, an exposure process may be performed, by theprojection system 532, to a layer of photoresist disposed on the wafer W, so as to pattern the layer of photoresist on the wafer W. - Reference is still made to
FIGS. 5 and 6C . The method M1 proceeds to operation S105, a cooling process is performed. In greater details, a cooling process may be performed to the wafer stage after the lithography process. In some embodiments, the cooling process can be done by, for example, emitted one or more modulated laser beams from thestage positioning modules FIG. 4B , the laser beam LB2 ofFIG. 4C , and/or the laser beam LB3 ofFIG. 4D . The modulated laser beams may transmit the respective beam splitters on the wafer stages 415 (such as thebeam splitters FIGS. 4A to 4D ), and may be received by the respective sensors in the wafer stages 415 (such as thesensors FIGS. 4A to 4D ). The processor in the wafer stages 415 (such as theprocessor 620 ofFIGS. 4A to 4D ) may decode the modulated laser beams and transmit the control signal to the controller in the wafer stages 415 (such as thecontroller 630 ofFIGS. 4A to 4D ). As a result, the controller can turn on a valve of thecable 440C connected to theliquid source 506 to introduce the liquid from the liquid source 506 (e.g., water) into thewafer stage 415, so as to cool down the wafer stages 415. - According to the aforementioned embodiments, it can be seen that the present disclosure offers advantages in fabricating semiconductor devices. It is understood, however, that other embodiments may offer additional advantages, and not all advantages are necessarily disclosed herein, and that no particular advantage is required for all embodiments. One advantage is that, a wireless control method is provided to control a wafer stage by emitting a modulated laser beam, which carries a control signal, toward a beam splitter on a wafer stage, the modulated laser beam may transmit through the beam splitter and may be received by a sensor in the wafer stage. Accordingly, processor and controller in the wafer stage are able to control the wafer stage according to the received control signal. With this configuration, a cable for transmitting control signal can be omitted, which will reduce about 30% to about 40% number of the cables. As a result, less cables will cause less particles (such as dust) falling on the table body, and will further reduce particle defect on the wafer, which in turn will improve die yield.
- In some embodiments of the present disclosure, a method includes moving a wafer stage to a first station on a table body of a lithography chamber; placing a wafer on a top surface of the wafer stage; emitting a first laser beam from a first laser emitter toward a first beam splitter on a first sidewall of the wafer stage, wherein a first portion of the first laser beam is reflected by the first beam splitter to form a first reflected laser beam, and a second portion of the first laser beam transmits through the first beam splitter to form a first transmitted laser beam; calculating a position of the wafer stage on a first axis based on the first reflected laser beam; after calculating the position of the wafer, moving the wafer stage to a second station on the table body; and performing a lithography process to the wafer when the wafer stage is at the second station.
- In some embodiments, calculating the position of the wafer stage on the first axis comprises receiving the first reflected laser beam by a sensor adjacent to the first laser emitter.
- In some embodiments, the method further includes emitting a second laser beam from a second laser emitter toward a second beam splitter on a second sidewall of the wafer stage, in which a first portion of the second laser beam is reflected by the second beam splitter to form a second reflected laser beam, and a second portion of the second laser beam transmits through the second beam splitter to form a second transmitted laser beam, and in which an incident surface of the second beam splitter is tiled about 45° relative to a top surface of the table body; and based on the second reflected laser beam, calculating the position of the wafer stage on a second axis perpendicular to the first axis.
- In some embodiments, an incident surface of the first beam splitter is substantially vertical to the top surface of the table body.
- In some embodiments, calculating the position of the wafer stage on the second axis comprises receiving the second reflected laser beam by a sensor disposed above the wafer stage.
- In some embodiments, moving the wafer stage to the second station on the table body includes: when the wafer stage is at the first station, emitting a modulated laser beam, which carries a position control signal, from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving the modulated laser beam transmitting through the first beam splitter by a sensor in the wafer stage; and based on the position control signal carried by the received modulated laser beam, moving the wafer stage.
- In some embodiments, the method further includes emitting a modulated laser beam, which carries a gas delivery control signal, from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving the modulated laser beam transmitting through the first beam splitter by a sensor in the wafer stage; and based on the gas delivery control signal carried by the received modulated laser beam, ejecting a gas out of the wafer stage.
- In some embodiments, the method further includes emitting a modulated laser beam, which carries a liquid delivery control signal, from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving the modulated laser beam transmitting through the first beam splitter by a sensor in the wafer stage; and based on the liquid delivery control signal carried by the received modulated laser beam, introducing a liquid into the wafer stage.
- In some embodiments of the present disclosure, a method includes moving a wafer stage to a first station on a table body of a lithography chamber; placing a wafer on a top surface of the wafer stage; emitting a first modulated laser beam from a first laser emitter toward a first beam splitter on a first sidewall of the wafer stage; receiving a first portion of the first modulated laser beam transmitting through the first beam splitter by a first sensor in the wafer stage; in response to the received first portion of the first modulated laser beam, moving the wafer stage from the first station to a second station on the table body; and performing a lithography process to the wafer when the wafer stage is at the second station.
- In some embodiments, the method further includes emitting a first unmodulated laser beam from the first laser emitter toward the first beam splitter on the first sidewall of the wafer stage; receiving, by the first stage positioning module, a second portion of the first unmodulated laser beam reflected by the first beam splitter; and calculating a position of the wafer stage on a first axis based on the received second portion of the first unmodulated laser beam.
- In some embodiments, the method further includes emitting a second unmodulated laser beam from a second laser emitter toward a second beam splitter on a second sidewall of the wafer stage; receiving, by a second sensor above the wafer stage, a portion of the second unmodulated laser beam reflected by the second beam splitter; and calculating the position of the wafer stage on a second axis.
- In some embodiments, an incident surface of the first beam splitter is substantially vertical to the top surface of the wafer stage, and an incident surface of the second beam splitter is tilted about 45° relative to the top surface of the wafer stage.
- In some embodiments, the method further includes emitting a second modulated laser to the first sensor in the wafer stage through the first beam splitter on the first sidewall of the wafer stage; and in response to the second modulated laser, ejecting a hydrogen gas out of the wafer stage, in which the wafer is placed on the wafer stage after the step of ejecting the hydrogen gas is complete.
- In some embodiments, the method further includes emitting a third modulated laser to the first sensor in the wafer stage through the first beam splitter on the first sidewall of the wafer stage; and in response to the third modulated laser, ejecting a dry air out of the wafer stage.
- In some embodiments, the method further includes after the lithography process is complete, emitting a fourth modulated laser to the first sensor in the wafer stage through the first beam splitter on the first sidewall of the wafer stage; and in response to the fourth modulated laser, introducing a water into the wafer stage by emitting a fourth modulated laser.
- In some embodiments of the present disclosure, a method includes moving a wafer stage to a first station on a table body of a lithography chamber; placing a wafer on a top surface of the wafer stage; determining a position of the wafer stage by a wireless operation that comprises emitting a first laser beam from a first laser emitter to a first sensor inside the wafer stage through a first beam splitter on a first sidewall of the wafer stage; and after determining the position of the wafer stage by the wireless operation, performing a lithography process to the wafer using a projection system above the wafer stage.
- In some embodiments, wherein an incident surface of the first beam splitter is substantially vertical to a top surface of the table body.
- In some embodiments, wherein an incident surface of the first beam splitter is tilted about 45° relative to a top surface of the table body.
- In some embodiments, wherein determining the position of the wafer stage by the wireless operation further comprises emitting a second laser beam from a second laser emitter to a second sensor above the wafer stage through a second beam splitter on a second sidewall of the wafer stage adjacent to the first sidewall of the wafer stage; and emitting a third laser beam from a third laser emitter to a third sensor inside the wafer stage through a third beam splitter on a third sidewall of the wafer stage opposite to the second sidewall of the wafer stage.
- In some embodiments, the method further includes, after the lithography process is complete, introducing water into the wafer stage through a cable connected to a fourth sidewall of the wafer stage opposite to the first sidewall of the wafer stage.
- The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
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US6331885B1 (en) * | 1997-09-19 | 2001-12-18 | Nikon Corporation | Stage apparatus, scanning type exposure apparatus, and device produced with the same |
US9594313B2 (en) * | 2008-12-19 | 2017-03-14 | Nikon Corporation | Movable body apparatus, exposure apparatus, exposure method, and device manufacturing method |
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- 2021-09-07 US US17/468,432 patent/US11556065B2/en active Active
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US6331885B1 (en) * | 1997-09-19 | 2001-12-18 | Nikon Corporation | Stage apparatus, scanning type exposure apparatus, and device produced with the same |
US9594313B2 (en) * | 2008-12-19 | 2017-03-14 | Nikon Corporation | Movable body apparatus, exposure apparatus, exposure method, and device manufacturing method |
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